import java.util.ArrayList;

public class LinkedListMap<K,V> implements Map<K,V> {

    private class Node{
        public K key;
        public V value;
        public Node next;
        public Node(K key,V value,Node next){
            this.key = key;
            this.value = value;
            this.next = next;
        }
        public Node(K key) {this(key,null,null);}
        public Node() {this(null,null,null);}

        @Override
        public String toString() {return key.toString()+" : "+value.toString();}
    }

    private Node dummyHead;
    private int size;

    public LinkedListMap(){
        this.dummyHead = new Node();
        this.size = 0;
    }

    private Node getNode(K key){
        Node cur = dummyHead.next;
        while(cur != null){
            if(cur.key.equals(key))
                return cur;
            cur = cur.next;
        }
        return null;
    }

    @Override
    public void add(K key, V value) {
        Node node = getNode(key);
        if(node == null){
            dummyHead.next = new Node(key,value,dummyHead.next);
            size++;
        }else
            node.value = value;

    }

    @Override
    public V remove(K key) {
        Node prev = dummyHead;
        while(prev.next != null){
            if(prev.next.key.equals(key))
                break;
            prev = prev.next;
        }
        if(prev.next != null){
            Node delNode = prev.next;
            prev.next = delNode.next;
            delNode.next = null;
            size--;
            return delNode.value;
        }
        return null;
    }

    @Override
    public boolean contains(K key) {
        return getNode(key) != null;
    }

    @Override
    public V get(K key) {
        Node node = getNode(key);
        return (node == null)?null:node.value;
    }

    @Override
    public void set(K key, V newValue) {
        Node node = getNode(key);
        if(node == null)
            throw new IllegalArgumentException(key + "doesn't exist!");
        node.value = newValue;
    }

    @Override
    public int getSize() {
        return size;
    }

    @Override
    public boolean isEmpty() {
        return size == 0;
    }

    public static void main(String[] args) {
        System.out.println("Pride and Prejudice");
        ArrayList<String> words = new ArrayList<>();
        if(FileOperation.readFile("pride-and-prejudice.txt",words)){
            System.out.println("Total words : "+ words.size());

            LinkedListMap<String,Integer> map = new LinkedListMap<>();
            for(String word:words){
                if(map.contains(word))
                    map.set(word,map.get(word) + 1);
                else
                    map.add(word,1);
            }
            System.out.println("Total different words : "+map.getSize());
            System.out.println("Frequency of PRIDE: " + map.get("pride"));
            System.out.println("Frequency of PREJUDICE: " + map.get("prejudice"));
        }
    }

}
